Sofa



FIG. 1 is a front perspective view of a sofa, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof taken from the left of FIG. 2;

FIG. 5 is a side elevation view thereof taken from the right of FIG. 2; and,

FIG. 6 is a is a top plan view thereof. 

I claim the ornamental design for a sofa, as shown and described. 